In the livestock industry, large round and square bales are shredded to feed and bed livestock. One type of bale processor currently in the market includes a flail drum longitudinally mounted for rotation inside a processing chamber. The flail drum is rotated and flails on the drum engage a bale inside the processing chamber, shred the baled material and discharge the shredded material out of the processor. The processors include at least one manipulator for manipulating the bale within the processing chamber to expose different portions of the bale to the flails. The manipulator may be one or more “feed rollers”. The manipulator is typically driven by a hydraulic motor that allows the user to change the speed and direction of rotation of the manipulator. Typically some kind of flow restrictor is used to limit the speed of the manipulator for proper processing.
High torque may be required to drive the manipulator when large bales are processed or when baled material becomes wound around the manipulator or wedged between the manipulator and the walls of the processor. High torque is often required when frozen bales are being manipulated.
Low cost hydraulic motors typically have a peak or maximum intermittent hydraulic oil supply pressure allowance dependant on the design parameters of the motor. Torque capabilities of hydraulic motors vary directly with size (displacement) of the motor. However, as the size of the motor increases, low cost commercial motor design often does not provide for proportional increases in torque or pressure capabilities and the pressure allowance is accordingly decreased.
If a hydraulic motor is used in an application where its maximum output torque is required and the power source (typically a tractor) can provide a peak pressure higher than the pressure allowance of the motor, then a pressure relief system must be used to protect the hydraulic motor from supply pressures exceeding the pressure allowance. Pressure relief systems are inconvenient, costly and limit the torque output of the motor.
Problems have been encountered with hydraulic motor reliability or operability in some bale processors of the type described and/or a pressure relief system has been required.